1. Field of the Invention
The invention relates to a method of detecting presence and motion for door control devices. It also relates to a door control device implementing the method of the invention.
2. Description of the Related Art
In the state of the art, the use of techniques based on the use of real images to control the opening and/or closing of a door control device, for example a lift door, has already been proposed.
Reference should be made to patent WO-A1-03/097506 which discloses a camera for detecting obstructions in the opening path of lift doors. The camera includes means for continuously recording video images, each recorded image being converted by image conversion means into a numerical vector. Then, a neurone network for recognizing obstructions is used to produce an alarm signal in order to control the opening and the closing of a door. Now, recognition by neurone network is a complicated technique that is difficult to implement in random lighting conditions.
Reference can also be made to document WO-A1-03/010719 which discloses a device for controlling access to a door. An analogue television camera is connected by its video signal output to a circuit for detecting an edge in upward or downward motion in an analogue video signal. Detection on an analogue video signal is a technique sensitive to radiofrequency noises.